1. Field of the Invention
The present invention relates to derivatives of N-acetl neuraminic acid and their use in medicine. More particularly the invention is concerned with particular physical forms of 5-acetamido-2,3,4,5-tetradeoxy-4-guanidino-D-glycero-D-galacto-non-2enopyr anosonic acid (the 4-guanidino analogue of DANA; also known as 5-(acetylamino)-2,6 andydro-3,4,5-trideoxy-4-guanidino-D-glycereo-D-galacto-non-2-enonic acid), pharmaceutical formulations thereof and their use in therapy.
2. Description of Related Art
PCT/AU91/00161 (publication no. WO91/16320) describes a number of derivatives of 5-acetamidino-2,3,5-trideoxy-D-glycero-D-galacto-non-2-enopyranosonic acid (2,3,-dideoxy-2,3-didehydro-N-acetyl-neuraminic acid; DANA) including the 4-guanidino analogue of DANA. The 4-guanidino analogue of DANA is prepared by the reaction of the corresponding O-acyl protected 4-amino analogue of DANA by reaction with S-methylisourea followed by deprotection, purification by chromatography and freeze-drying.
The structure of the 4-guanidino analogue of DANA is shown below: ##STR1##
We have now found that the compound of formula (1) can be obtained in crystalline form.